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Cao YX, Silalai P, Liu CF, Yu KY, Bao X, Zhao XH, Saeeng R, Fan CA. Hypervalent-Iodine(III)-Mediated Tandem Oxidative Dearomatization/Aziridination of Phenolic Amines: Synthesis of Functionalized Unactivated Aziridines. Chemistry 2021; 27:8473-8478. [PMID: 33844345 DOI: 10.1002/chem.202100762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Indexed: 11/11/2022]
Abstract
A new hypervalent-iodine(III)-mediated tandem reaction involving oxidative dearomatization and in situ aziridination of phenolic amines is described, providing a mild and effective method for the assembly of structurally interesting and synthetically useful aziridines. Importantly, the densely functionalized aziridines resulting from this unprecedented tandem reaction offer a platform for expeditious access to architecturally diverse aza-heterocycles through transformations initiated by selective ring-opening of aziridines.
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Chen X, Lloyd S, Bao X. 156 MYC-CPSF-HNRNPA3 cooperation promotes epidermal progenitor maintenance through modulating intronic transcription termination. J Invest Dermatol 2021. [DOI: 10.1016/j.jid.2021.02.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Bao X, Weiner J, Meckes O, Dommisch H, Schaefer AS. Entamoeba gingivalis Exerts Severe Pathogenic Effects on the Oral Mucosa. J Dent Res 2021; 100:771-776. [PMID: 33792418 PMCID: PMC8217899 DOI: 10.1177/00220345211004498] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The protozoan Entamoeba gingivalis colonizes the healthy oral mucosa with a prevalence of 15%. Colonization can be asymptomatic, and it is considered not pathogenic. However, it is able to invade lacerated oral mucosa, where it ingests fragments of live cells, suggesting pathogenous potential. Here, we characterized the transcriptomes of gingival cells after infection with E. gingivalis using RNA sequencing and observed pathogen interaction with the epithelial monolayer barrier by scanning electron microscopy. In epithelial and fibroblast cells, strongest differential expression showed gene set “chemokines and inflammatory molecules in myeloid cells” (area under the curve [AUC] = 0.9, effect size 5.15, adjusted P = 3.1 × 10−19) and “cell cycle and growth arrest” (AUC = 0.91, effect size = 4.56, adjusted P = 4.8 × 10−9), respectively. The most upregulated genes were TNF (fold change 430) and IL8 (fold change 359) in epithelial cells and ZN331 (fold change 18) in fibroblasts. We showed that E. gingivalis killed live epithelial cells by trogocytosis, demonstrating strong pathogenic potential.
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Bao X, Wang S, Housden R, Hajnal J, Rhode K. A Constant-Force End-Effector With Online Force Adjustment for Robotic Ultrasonography. IEEE Robot Autom Lett 2021; 6:2547-2554. [PMID: 33748416 PMCID: PMC7968128 DOI: 10.1109/lra.2021.3061329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/06/2021] [Indexed: 11/18/2022]
Abstract
In this letter, we propose a novel constant-force end-effector (CFEE) to address current limitations in robotic ultrasonography. The CFEE uses a parallel, motor-spring-based solution to precisely generate constant operating forces over a wide range and enable the ultrasound (US) probe to adapt to the abdominal contours autonomously. A displacement measurement unit was developed to realize the acquisition of probe position and precise control of the operating force. Moreover, the operating force can be adjusted online to maintain safety and continuity of operation. Simulations and experiments were carried out to evaluate the performance. Results show that the proposed CFEE can provide constant forces of 4-12 N with displacements of 0-8 mm. The maximum relative error of force generation is 8.28%, and the accuracy and precision for displacement measurement are 0.29 mm and ±0.16 mm, respectively. Various operating forces can be adjusted online during the same operation. Ultrasound images acquired by the proposed CFEE are of equally good quality compared to a manual sonographer scan. The proposed CFEE would have potential further medical applications.
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Yan X, Liu L, Zhang Y, Song T, Liang Y, Liu Z, Bao X, Mao L, Qiu Y. Perioperative Enteral Nutrition Improves Postoperative Recovery for Patients with Primary Liver Cancer: A Randomized Controlled Clinical Trial. Nutr Cancer 2020; 73:1924-1932. [PMID: 32875913 DOI: 10.1080/01635581.2020.1814824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The role of perioperative protein-enriched enteral nutrition for patients with primary liver cancer is unclear. We investigated the efficacy of perioperative protein-enriched enteral nutrition for patients with primary liver cancer followed hepatectomy. METHODS Patients with primary liver cancer that underwent hepatectomy between January 2016 and 2018 were enrolled. Patients in the treatment group was given enteral nutrition (TP-MCT) in addition to the regular diet. The primary outcome measures were duration of hospital stay and length of postoperative hospital stay. Secondary outcome measures included time to first flatus and time to first defecation. RESULTS There was a significant reduction of time to first flatus and time to first defecation in the treatment group, when compared with the control group (time to first flatus: P = 0.001, time to first defecation: P < 0.001). CONCLUSIONS It is found that addition of protein-enriched enteral nutrition (TP-MCT) improved postoperative recovery for patients with primary liver cancer following hepatectomy, with a significant reduction in time to first flatus and time to first defecation.
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Gu YQ, Xia Y, Zhang SM, Bao X, Wu HM, Bian SS, Huang LY, Meng G, Niu KJ. [Method of dietary nutritional status assessment and its application in cohort study of nutritional epidemiology]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 2020; 41:1145-1150. [PMID: 32741185 DOI: 10.3760/cma.j.cn112338-20200110-00027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Minimizing the burden on study subjects and assessing the general dietary nutritional status as accurately as possible are the basis of a nutritional epidemiological cohort study in the general population. While introducing the main dietary nutrition assessment methods, this paper manly describes the basic contents and principles for the development of food frequency questionnaire, and briefly illustrates the problems and solutions for the development of area specific food frequency questionnaires by taking the example of Tianjin Chronic Low-grade Systemic Inflammation and Health (TCLSIH) cohort study. Finally, discusses preliminarily the necessity and possibility of developing a national food frequency questionnaire.
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Roth-Carter Q, Godsel L, Koetsier J, Broussard J, Burks H, Fitz G, Huffine A, Amagai S, Lloyd S, Kweon J, Tsoi L, Swindell W, Urciuoli G, Missero C, Bao X, Gudjonsson J, Green K. 225 Desmoglein 1 deficiency in knockout mice impairs epidermal barrier formation and results in a psoriasis-like gene signature in E18.5 embryos. J Invest Dermatol 2020. [DOI: 10.1016/j.jid.2020.03.230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Collineau L, Chapman B, Bao X, Sivapathasundaram B, Carson CA, Fazil A, Reid-Smith RJ, Smith BA. A farm-to-fork quantitative risk assessment model for Salmonella Heidelberg resistant to third-generation cephalosporins in broiler chickens in Canada. Int J Food Microbiol 2020; 330:108559. [PMID: 32599476 DOI: 10.1016/j.ijfoodmicro.2020.108559] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 10/18/2019] [Accepted: 02/09/2020] [Indexed: 12/27/2022]
Abstract
Salmonella Heidelberg resistant to ceftiofur (a third-generation cephalosporin antimicrobial agent) in broiler chicken products pose a risk to public health in Canada. The objective of this study was to assess the extent of that risk and to evaluate the effect of intervention measures along the agri-food chain. A stochastic farm-to-fork quantitative microbial risk assessment model was developed following the Codex Alimentarius Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance. Different scenarios were analyzed to assess the individual relative effects of 18 possible interventions in comparison to a baseline scenario. The baseline scenario represented the first year of on-farm antimicrobial use surveillance in the Canadian broiler industry and the year before an industry-imposed ban on the preventive use of antimicrobials of very high importance to human health (2013), where 31.3% of broiler flocks consisted of birds to which ceftiofur was administered. The baseline scenario predicted an average probability of illness of 1.1 per 100,000 servings (SE: 0.064 per 100,000), corresponding to an average of 22,000 human infections (SE: 1900) with ceftiofur-resistant S. Heidelberg per year, which is likely an overestimation. This risk was reduced by 90% or 20% when two separate scenarios designed to capture the effect of withdrawing preventive ceftiofur use from poultry production were simulated using different approaches; data used for the former scenario were confounded by other potential concomitant control measures (e.g. Salmonella vaccination programme), so the true effect likely lies somewhere between the two estimates. A theoretical 'worst case' scenario where all flocks had birds exposed to ceftiofur increased the risk by 107%. A 50% reduction in the probability of human prior exposure to antimicrobials, which has a selective and competitive effect for Salmonella spp. following ingestion of contaminated products, reduced the risk by 65%. Other promising measures that could be considered for further risk management included improved cleaning and disinfection between broiler flocks on farm (risk reduction by 26%), exclusive use of air chilling (risk reduction by 34%), and the improvement of meat storage and preparation conditions, e.g., no temperature abuse at retail (risk reduction by 88%). These findings showed the importance of a structured approach to assessing and potentially implementing effective interventions to reduce the risk associated with ceftiofur-resistant S. Heidelberg at different steps along the agri-food chain. Major data gaps included information on concentrations of resistant bacteria, cross contamination at processing and how ceftiofur-resistant S. Heidelberg behave in comparison with susceptible ones, e.g., in terms of growth and survival ability, as well as pathogenicity and virulence.
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Bao X, Wiehe R, Dommisch H, Schaefer A. Entamoeba gingivalis Causes Oral Inflammation and Tissue Destruction. J Dent Res 2020; 99:561-567. [DOI: 10.1177/0022034520901738] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A metagenomics analysis showed a strongly increased frequency of the protozoan Entamoeba gingivalis in inflamed periodontal pockets, where it contributed the second-most abundant rRNA after human rRNA. This observation and the close biological relationship to Entamoeba histolytica, which causes inflammation and tissue destruction in the colon of predisposed individuals, raised our concern about its putative role in the pathogenesis of periodontitis. Histochemical staining of gingival epithelium inflamed from generalized severe chronic periodontitis visualized the presence of E. gingivalis in conjunction with abundant neutrophils. We showed that on disruption of the epithelial barrier, E. gingivalis invaded gingival tissue, where it moved and fed on host cells. We validated the frequency of E. gingivalis in 158 patients with periodontitis and healthy controls by polymerase chain reaction and microscopy. In the cases, we detected the parasite in 77% of inflamed periodontal sites and 22% of healthy sites; 15% of healthy oral cavities were colonized by E. gingivalis. In primary gingival epithelial cells, we demonstrated by quantitative real-time polymerase chain reaction that infection with E. gingivalis but not with the oral bacterial pathogen Porphyromonas gingivalis strongly upregulated the inflammatory cytokine IL8 (1,900 fold, P = 2 × 10–4) and the epithelial barrier gene MUC21 (8-fold, P = 7 × 10–4). In gingival fibroblasts, we showed upregulation of the collagenase MMP13 (11-fold, P = 3 × 10–4). Direct contact of E. gingivalis to gingival epithelial cells inhibited cell proliferation. We indicated the strong virulence potential of E. gingivalis and showed that the mechanisms of tissue invasion and destruction are similar to the colonic protozoan parasite E. histolytica. In conjunction with abundant colonization of inflamed periodontal sites and the known resistance of Entamoeba species to neutrophils, antimicrobial peptides, and various antibiotics, our results raise the awareness of this protozoan as a potential and, to date, underrated microbial driver of destructive forms of periodontitis.
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Cao X, Gu Y, Fu J, Vu TQC, Zhang Q, Liu L, Meng G, Yao Z, Wu H, Bao X, Zhang S, Wang X, Sun S, Zhou M, Jia Q, Song K, Wu Y, Niu K. Excessive daytime sleepiness with snoring or witnessed apnea is associated with handgrip strength: a population-based study. QJM 2019; 112:847-853. [PMID: 31297519 DOI: 10.1093/qjmed/hcz178] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/01/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Sarcopenia is emerging as an important public health problem, and evidences have determined that poor sleep is associated with muscle strength, but the potential effects of excessive daytime sleepiness (EDS), snoring and witnessed apnea on handgrip strength have not been evaluated. AIM We aimed to examine the association between EDS, snoring, witnessed apnea and muscle strength in an adult population. DESIGN Cross-sectional study. METHODS This cross-sectional study comprised 19 434 adults. Handgrip strength was measured using a handheld digital dynamometer. EDS was assessed by Epworth Sleepiness Scale, snoring and witnessed apnea during sleep were reported through simple yes/no questions. Analysis of covariance was carried out to determine the association between EDS with snoring or witnessed apnea and muscle strength. RESULTS The means (95% confidence interval) for average handgrip strength/body weight (kg/kg) across symptoms categories were 0.396 (0.333-0.472), 0.393 (0.330-0.467), 0.396 (0.333-0.471) and 0.386 (0.325-0.460) (P < 0.0001), respectively. Similar results were observed with maximal handgrip strength/body weight (kg/kg). CONCLUSIONS Self-reported EDS accompanied with snoring or apnea is associated with lowest handgrip strength, independently of confounding factors. Whether improvement of EDS, snoring and apnea, can ameliorate age-associated decline in muscle strength warrants further studies.
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Mehta S, Fiorelli R, Li J, Bao X, DeRogatis A, Pennington-Krygier C, Kim S, Sanai N. Phase 0 trial of ceritinib in brain metastases and recurrent glioblastoma. Ann Oncol 2019. [DOI: 10.1093/annonc/mdz243.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Sanai N, Tien AC, Li J, Bao X, DeRogatis A, Fujita Y, Pennington-Krygier C, Kim S, Mehta S. A phase 0/II clinical trial of a CDK4/6 inhibitor in aggressive meningioma patients. Ann Oncol 2019. [DOI: 10.1093/annonc/mdz243.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Tien A, Li J, Bao X, DeRogatis A, Fujita Y, Pennington-Krygier C, Kim S, Mehta S, Sanai N. OS8.1 A phase 0/2 clinical trial of a CDK4/6 inhibitor in aggressive meningioma patients. Neuro Oncol 2019. [DOI: 10.1093/neuonc/noz126.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
BACKGROUND
New approaches are urgently needed for aggressive meningiomas, which remain largely incurable. Forkhead Box M1 (FOXM1) has been identified as a master transcription factor in aggressive meningiomas and Cyclin D-dependent Kinases (CDK) are positive regulators of cell-cycle entry, promoting tumorigenesis through FOXM1 activation. We evaluated the tumor pharmacokinetics (PK), tumor pharmacodynamics (PD), and preliminary clinical response of ribociclib, a selective CDK4/6-inhibitor, in aggressive meningioma patients.
MATERIAL AND METHODS
Eight aggressive WHO Grade II/III meningioma patients with intact RB expression were enrolled and administered oral ribociclib daily (900mg) for 5 days prior to tumor resection. Plasma, tumor, and cerebrospinal fluid (CSF) samples were collected at 2, 8, or 24 h after the last dose. Total and unbound drug concentrations were determined using a validated LC-MS/MS method. PD effects, including RB and FoxM1 phosphorylation, were compared to matched archival tissue. Patients with PK and PD responses in tumor tissue, defined as unbound ribociclib concentration > 5-fold in vitro IC50 (0.04µM) and >20% decrease in pRB levels, respectively, were enrolled into an exploratory Phase 2 cohort.
RESULTS
The median CSF concentration of ribociclib was 0.25 µM. In tumor tissue, the median unbound ribociclib concentration was 1.36 µM and the median unbound tumor-to-plasma ratio was 5.34. Suppression of G1-to-S phase was inferred in tumors with declining FoxM1 phosphorylation (50%), RB phosphorylation (38%), and cellular proliferation (75%). Four patients demonstrated concurrent PK and PD responses and were graduated to continuous ribociclib therapy. At one year, two of these patients (one Grade II and one Grade III) demonstrate partial responses per RANO criteria.
CONCLUSION
Ribociclib achieves pharmacologically-active concentrations in aggressive meningioma tissue. Target modulation was demonstrated by a decrease in FOXM1-mediated tumor proliferation. Further investigation of ribociclib as a therapeutic strategy for aggressive meningiomas is warranted.
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Fiorelli R, Li J, Bao X, DeRogatis A, Pennington-Krygier C, Kim S, Mehta S, Sanai N. OS4.2 Phase 0 trial of Ceritinib in brain metastasis and recurrent glioblastoma. Neuro Oncol 2019. [DOI: 10.1093/neuonc/noz126.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
BACKGROUND
Ceritinib is an orally bioavailable, small molecule inhibitor for ALK/IGFR1/FAK, which are highly expressed in glioblastoma and brain metastases. Preclinical and clinical data suggest that ceritinib has activity in central nervous system (CNS) malignancies, but to date there is no direct evidence in patients. This study assessed the pharmacokinetics (PK) and pharmacodynamics (PD) of ceritinib in recurrent glioblastoma and brain metastasis patients.
MATERIALS AND METHODS
Three brain metastasis and seven glioblastoma patients with high expression of pSTAT5b/pFAK/pIGFR1 were enrolled and treated with oral ceritinib daily (750 mg) for 10 days prior to tumor resection. Plasma, tumor, and cerebrospinal fluid (CSF) samples were collected at ~ 4 and 24 h following the last dose. Total and unbound drug concentrations were determined using LC-MS/MS. PD response was assessed by immunohistochemical analysis of pALK, pFAK, pIGFR1, and pIRS1 staining in treated tumor and matched archival tissues.
RESULTS
Ceritinib was highly bound to human plasma protein (median fraction unbound (Fu), 1.4%) and to brain tumor tissue (median Fu, 0.073% and 0.14% in enhancing and non-enhancing regions respectively). There was a large interindividual variability in drug CNS penetration, with the median unbound concentrations in enhancing, non-enhancing, and CSF of 0.040, 0.006, and 0.012 µM, respectively. The median unbound tumor-to-plasma ratio was 2.44 and 0.33 in enhancing and non-enhancing areas, respectively. In one patient with brain metastasis, drug binding to enhancing tumor was significantly lower (Fu, 1.62%), resulting in a higher unbound drug tumor concentration and CSF concentration as compared to those in glioblastoma patients. In all patients, no changes in PD markers were detected.
CONCLUSION
Ceritinib is highly bound to plasma proteins and tumor tissues. Unbound drug concentrations achieved in brain metastasis and glioblastoma are unlikely sufficient for target modulation.
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Chen X, Lloyd S, Kweon J, Gamalong G, Bao X. 280 Transcription termination modulates human epidermal proliferation and differentiation. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.07.281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hou M, Bao X, Luo F, Chen X, Liu L, Wu M. HMGA2 Modulates the TGFβ/Smad, TGFβ/ERK and Notch Signaling Pathways in Human Lens Epithelial-Mesenchymal Transition. Curr Mol Med 2019; 18:71-82. [PMID: 29974827 DOI: 10.2174/1566524018666180705104844] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/24/2018] [Accepted: 07/02/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND OBJECTIVE Multiple signaling pathways coordinately promote epithelial-mesenchymal transition (EMT) in lens epithelial cells (LECs), where transforming growth factor beta (TGFβ)-mediated signaling plays a central role. But the mechanism of crosstalk among these pathways remains obscure. The objective of this study is to investigate the regulatory effect of the high mobility group protein A2 (HMGA2) on the signaling pathways in lens fibrosis. METHODS The human anterior capsulorhexis specimens were collected. The human SRA01/04 LEC line was cultured and treated with recombinant human TGFβ2 (5ng/ml). For inhibition of signaling pathways, a selective inhibitor SB431542, U0126 or DAPT was added to LECs respectively. The specific small interfering RNA (siRNA) were transfected to LECs for gene silence. The mRNAs expressions were measured by realtime PCR and the proteins expressions were determined by western blot and immunofluorescent staining. RESULTS HMGA2 and EMT markers α-smooth muscle actin (SMA), fibronectin (FN) and collagen type I (Col I) were overexpressed in human ASC specimens and TGFβ2 stimulated EMT in LECs. While blockage of EMT by a selective inhibitor of TGFβ/Smad, TGFβ/extracellular signal-regulated kinase (ERK) or Notch signaling pathway could significantly inhibited HMGA2 protein expression. And silence of HMGA2 by siRNA could significantly inhibit TGFβ2 induced expression of EMT markers including FN, Col I, collagen type IV (Col IV), key transcription factors Snail and Slug, and remarkably upregulate the epithelial markers E-cadherin and tight junction protein (ZO-1). In addition, silence of HMGA2 gene could abrogate TGFβ2 induced phosphorylation of Smad2, Smad3 as well as ERK1/2. Blockage of HMGA2 could also inhibit the upregulation of Jagged1, Notch2, and Notch3 induced by TGFβ2. CONCLUSION This study indicated that HMGA2 functions as a shared effector in TGFβ2- induced lens fibrosis, modulating the signaling network necessary for EMT in a positive feedback loop.
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Bao X, Wang Q, Zhu J. Remote C(sp 3 )-H Arylation and Vinylation of N-Alkoxypyridinium Salts to δ-Aryl and δ-Vinyl Alcohols. Chemistry 2019; 25:11630-11634. [PMID: 31321814 DOI: 10.1002/chem.201902918] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Indexed: 02/02/2023]
Abstract
The reaction of readily available and bench-stable N-alkoxypyridinium salts with arylboronic and vinylboronic acids afforded δ-aryl and δ-vinyl alcohols, respectively, in the presence of fac-Ir(ppy)3 and Cu(OTf)2 dual catalysts. The reaction takes place through a domino process involving the reductive generation of alkoxyl radicals, 1,5-hydrogen atom transfer (1,5-HAT) and the copper-catalyzed cross-coupling reaction of the resulting translocated carbon radicals with boronic acids. Complementary to the Minisci reaction, this method allows for the arylation of nucleophilic alkyl radicals with both electron-rich and electron-poor arenes under mild reaction conditions.
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Jong JAW, Bao X, Wang Q, Zhu J. Formal [4+1] Cycloaddition ofo‐Aminobenzyl Chlorides with Isocyanides: Synthesis of 2‐Amino‐3‐Substituted Indoles. Helv Chim Acta 2019. [DOI: 10.1002/hlca.201900002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Bao X, Wang Q, Zhu J. Copper-catalyzed remote C(sp 3)-H azidation and oxidative trifluoromethylation of benzohydrazides. Nat Commun 2019; 10:769. [PMID: 30770833 PMCID: PMC6377619 DOI: 10.1038/s41467-019-08741-w] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/15/2019] [Indexed: 12/02/2022] Open
Abstract
The Hofmann-Löffler-Freytag (HLF) reaction is a prototypical example of radical-based remote functionalization of unactivated C(sp3)-H bond. While 1,5-hydrogen atom transfer (1,5-HAT) of the amidyl radical is thermodynamically favorable and is well-established, the method for the subsequent functionalization of the translocated carbon radical is still limited. We report herein two catalytic remote C(sp3)-H functionalization protocols. Cu(MeCN)4PF6-catalyzed reaction of 2-alkyl benzohydrazides 3 with TMSN3 in the presence of MeCO2OtBu affords the γ-azido amides 4, while CuCl-catalyzed reaction of 3 with Togni's reagent provides 2-(β-trifluoromethylvinyl)benzamides 5 via an oxidative δ-trifluoromethylation of the alkyl group. Mechanistic studies suggest that the γ-azidation of benzohydrazides 3 goes through 1,5-HAT followed by a Cu-mediated azido transfer cascade, while the oxidative δ-trifluoromethylation of 3 proceeds via, after 1,5-HAT process, a radical-polar crossover mechanism.
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Bao X, Wang Q, Zhu J. Dual Photoredox/Copper Catalysis for the Remote C(sp3
)−H Functionalization of Alcohols and Alkyl Halides by N
-Alkoxypyridinium Salts. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201813356] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bao X, Wang Q, Zhu J. Dual Photoredox/Copper Catalysis for the Remote C(sp3
)−H Functionalization of Alcohols and Alkyl Halides by N
-Alkoxypyridinium Salts. Angew Chem Int Ed Engl 2019; 58:2139-2143. [DOI: 10.1002/anie.201813356] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 12/12/2018] [Indexed: 11/11/2022]
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Bao X, Gu X, Zhang W. User-centric quality of experience optimized resource allocation algorithm in VLC network with multi-color LED. OPTICS EXPRESS 2018; 26:27826-27841. [PMID: 30469841 DOI: 10.1364/oe.26.027826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/13/2018] [Indexed: 06/09/2023]
Abstract
Visible light communication (VLC) can provide indoor illumination while achieving high network throughput. In order to mitigate the performance degradation caused by inter-cell interference (ICI) and support multiple users, this paper utilizes the white LED synthesized by multi-color light sources as indoor illumination and signal transmissions. Compared with ordinary LEDs, multi-color LEDs not only has excellent color rendering index, but also realize multi-channel parallel transmission, which greatly improves the transmission speed of VLC. Meanwhile, we propose a user-centric (UC) quality of experience (QoE) optimization scheduling scheme for the VLC down-link system. In contrast to the traditional network-centric (NC) design, the UC scheme is based on the user-centric dynamic construction and adjustment of the network model. Furthermore, in order to further analyze the performances of the illuminations and signal transmissions of the VLC system with multi-color LED, we consider the system model under two scenarios of 3-color and 4-color synthetic white LEDs. For these two different LED composition and optimization problems, we design a new greedy algorithm to allocate optical bandwidth, and dynamically searched for the optimal access point user equipment (AP-UE) link based on optimization of the UEs' QoE values. In order to analyze the robustness of the algorithm, we further consider the influences of UEs on the transmission performance under different UEs' spatial distributions, e.g., uniform and Poisson distributions. The simulation results illustrate that the proposed scheme guarantees the UEs' QoE while offering illumination quality. Meanwhile, compared to ordinary LEDs and the traditional network-centric (NC) design, our proposed scheme can schedules more UEs.
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Bao X, Yokoe T, Ha TM, Wang Q, Zhu J. Copper-catalyzed methylative difunctionalization of alkenes. Nat Commun 2018; 9:3725. [PMID: 30213939 PMCID: PMC6137206 DOI: 10.1038/s41467-018-06246-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 08/21/2018] [Indexed: 12/02/2022] Open
Abstract
Trifluoromethylative difunctionalization and hydrofunctionalization of unactivated alkenes have been developed into powerful synthetic methodologies. On the other hand, methylative difunctionalization of olefins remains an unexplored research field. We report in this paper the Cu-catalyzed alkoxy methylation, azido methylation of alkenes using dicumyl peroxide (DCP), and di-tert-butyl peroxide (DTBP) as methyl sources. Using functionalized alkenes bearing a tethered nucleophile (alcohol, carboxylic acid, and sulfonamide), methylative cycloetherification, lactonization, and cycloamination processes are subsequently developed for the construction of important heterocycles such as 2,2-disubstituted tetrahydrofurans, tetrahydropyrans, γ-lactones, and pyrrolidines with concurrent generation of a quaternary carbon center. The results of control experiments suggest that the 1,2-alkoxy methylation of alkenes goes through a radical-cation crossover mechanism, whereas the 1,2-azido methylation proceeds via a radical addition and Cu-mediated azide transfer process. While the trifluoromethylative difunctionalization of unactivated alkenes has been largely explored, methylative difunctionalization remains underinvestigated. Here, the authors report copper-catalyzed alkoxy- and azido-methylation reactions of alkenes leading to important synthetic building blocks and valuable O- and N-heterocycles.
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Bao X, Duan J, Yan Y, Ma X, Zhang Y, Wang H, Ni D, Wu S, Peng C, Fan Y, Gao Y, Li X, Chen J, Du Q, Zhang F, Zhang X. Upregulation of long noncoding RNA PVT1 predicts unfavorable prognosis in patients with clear cell renal cell carcinoma. Cancer Biomark 2018; 21:55-63. [PMID: 29081406 DOI: 10.3233/cbm-170251] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Renal cell carcinoma (RCC) is one of the most malignant genitourinary diseases worldwide. Long noncoding RNAs (lncRNAs) are a class of noncoding RNAs in the human genome that are involved in RCC initiation and progression. OBJECTIVE To investigate the expression of PVT1 in ccRCC and evaluate its correlation with clinicopathologic characteristics and patients' survival. METHODS Quantitative real-time PCR was performed to examine PVT1 expression in 129 ccRCC tissue samples and matched adjacent normal tissue samples. The relationship of PVT1 expression with clinicopathologic characteristics and clinical outcome was evaluated. RESULTS We identified the lncRNA PVT1, which was upregulated in clear cell renal cell carcinoma (ccRCC) tissues when compared with corresponding controls. Furthermore, PVT1 expression was positively associated with gender, tumor size, pT stage, TNM stage, and Fuhrman grade. Kaplan-Meier survival analysis showed that patients with high PVT1 expression had shorter disease-free survival (DFS) and overall-survival (OS) than those with low PVT1 expression, and multivariate analysis identified PVT1 as an independent prognostic factor in ccRCC. CONCLUSIONS PVT1 may be an oncogene as well as may promote metastasis in ccRCC and could serve as a potential biomarker to predict the prognosis of ccRCC patients.
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Bao X, Liu H. Effect of intermittent hypoxia training for dizziness: A randomized controlled trial. Ann Phys Rehabil Med 2018. [DOI: 10.1016/j.rehab.2018.05.801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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